Definition: An abacus is an ancient kind of calculating machine that keeps track of numbers by moving beads in grooves or along bars.
Other Definition: An abacus (plurals abacuses or abaci), also called a counting frame, is a calculating tool for performing arithmetical processes, often constructed as a wooden frame with beads sliding on wires. The user, called an abacist, slides counters by hand on rods or in grooves.
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Definition: A telescope is an optical device used to view things at great distances. Astronomers use telescopes to observe the movements of the stars and planets.
Other Definition: A telescope is an instrument designed for the observation of remote objects and the collection of electromagnetic radiation. The earliest known telescopes are credited to three individuals, Hans Lippershey and Zacharias Janssen, spectacle-makers in Middelburg, and Jacob Metius of Alkmaar also known as Jacob Adriaanszoon. Telescope was a name invented in 1611 by Prince Frederick Sesi while watching a presentation of Galileo Galilei’s instrument, which was based on Hans Lippershey’s design.
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